1. Field of the Invention
The present invention relates to a system for analysis of partial discharge defects of a gas insulated switchgear, and more particularly, to a system for analysis of partial discharge defects of a gas insulated switchgear capable of allowing a user to precisely analyze a defect of a gas insulated switchgear due to a partial discharge, by providing both partial discharge signal information on a partial discharge signal sensed by a detecting sensor, and detection signal information on a detection signal sensed by one or more neighboring sensors adjacent to the detecting sensor, to a monitor.
2. Background of the Invention
A substation is located between a transmission line and a distribution line, and converts a high transmission voltage into a low distribution voltage.
The substation is installed with a switchgear for connecting the transmission line to the distribution line, or for separating the two lines from each other. Such a switchgear is called a distribution line switchgear.
The distribution line switchgear is divided into a hydraulic type, a magnetic type, an air type, etc., and a gas insulated switchgear (GIS) using SF6 having an excellent insulating property is being widely used.
However, despite such an excellent insulating property of the gas insulated switchgear, when an insulation accident occurs on a power system, a social confusion, an economical loss, etc. may be caused. Thus, it is absolutely required to prevent such an insulation accident.
Accordingly, a technique for automatically sensing a partial discharge, a representative cause of a thermal degradation of the gas insulated switchgear, is being actively researched.
The partial discharge (PD) is a discharge phenomenon which partially occurs along the periphery or the inside of an insulator, under a stress of a high voltage. The partial discharge is generally generated from a partial crack due to a gap naturally formed, or a thermal degradation of the switchgear.
The partial discharge may cause power loss due to power leakage. In some cases, the partial discharge may cause an irreversible physical or chemical change on an insulating material. This may cause complete cutoff of power supply through a distribution line, or explosion of equipment.
Such a partial discharge of the conventional gas insulated switchgear (GIS) is diagnosed through an artificial intelligence technique such as an artificial neural network algorithm or a fuzzy inference technique. More specifically, an input variable, feature amount data, is extracted through a pattern analysis with respect to measured data on a partial discharge, and a result is inferred through an artificial intelligence technique such as an artificial neural network algorithm or a fuzzy inference technique.
FIG. 1 is a view schematically illustrating a configuration of an online partial discharge diagnosis system in accordance with the conventional art.
As shown in FIG. 1, a partial discharge signal is sensed by a discharge detecting sensor (not shown) installed at a switchgear, and information on the sensed signal is collected by a data acquisition unit (DAU) 1. Then, the information is stored in a database server 3 via a DAU communication server 2.
Information on a partial discharge charge amount and the number of times of partial discharge, among the partial discharge signal, is stored with time information. A defect pattern is recognized through a partial discharge diagnosis algorithm 4, and a chart indicating a defect type and an occurred signal is output to a screen 5.
A diagnosis screen indicating a partial discharge, output to the screen 5, may be implemented in various manners. For instance, the diagnosis screen indicating a partial discharge, may be implemented as a list of partial discharge occurrence events, a determination result chart, a 2D chart, a 3D chart, etc.
The list of partial discharge occurrence events displays an occurrence history of all partial discharges, and the determination result chart displays a result on analysis of defects of partial discharge occurrence events, in the form of a proportion with respect to each defect. The 2D chart displays a phase, a size and the number of times of a partial discharge signal, in a 2D form. And the 3D chart displays a phase, a size and the number of times of a partial discharge signal, in a 3D form.
The data means data on a partial discharge signal of a single sensor, selected from the list of partial discharge occurrence events.
However, in the conventional system for diagnosis of a partial discharge of a gas insulated switchgear, only information on a partial discharge signal sensed by the detecting sensor is provided to a monitor. This may cause a difficulty in precisely diagnosing whether a defect of the switchgear exists on a position where a partial discharge has occurred, and a cause of the occurrence of the defect.